Means and method for molding hollow concrete beams



A. M; PENNINGTON Sept. 12, 1944.

MEANS AND METHOD FOR MOLDING HOLLOW CONCRETE BEAMS Filed Sept. 29, 1942 I MATHER PENN 1 NGTON /fiwfi Attorneys.

Patented Sept. 12, 1944 UNITED STATES. PATENT 9mm:

MEANS AND METHOD FOR MOLDING HOLLOW CONCRETE BEAMS Alan Mather Pennington, Eddington, Herne Bay, England Application September 29, 1942, Serial No. 466,058 In Great Britain October 18, .1941

3 Claims.

This invention relates to reinforced concrete floors, ceilings, roofs and the like, andis particularly applicable to those floors, ceilings, roofs and the like (hereinafter briefly referred to as floors) wherein precast reinforced concrete cavity beams or blocks are employed and are placed side by side on their supports and grouted or otherwise connected together to form continu ous floors or the like of any required areas, shapes.

'or strengths. 1

The chief object of the invention is to effect improvements in the manufacture of such concrete cavity beams or the like, to be used for the members arranged adjacent to the core so as to be adapted to assist in maintaining against collapse the cavity to be formed by the core, applying around the said core concrete that is Just off the slump (as hereinafter defined), subjecting the concrete to a consolidating treatment, as

by applying vibration, and finally withdrawing the core before appreciable contraction of the cavity has occurred in the process of the setting or hardening of the concrete.

The mold for use by this method preferably comprises a pallet of channel form adapted to support a component during and after the setting process, and removable upper parts adapted to be clamped to the said pallet so as to complete the sides of the mold. The said upper parts may be of various depths so that they may be used alternatively to be clamped to one and the same pallet, in order that components of various depths as desired may be cast upon the said pallet. The said mold may be adapted to be crossed by rodlike members, as for example boltsjadapted to assist'in the correct positioning of cores and/or reinforcing members before and during the casting of the said components.

Preferably some of the said reinforcing members are so arranged as to form a framework around the hollow interior r cavity which'any core causes to be formed in the casting, which framework is adapted to assist in maintaining the shape of the said hollow interior after withdrawal'of the said-core.

A component according to the invention is so formed as to have a hollow interior of circular or other convenient cross-sectional shape, this .hollow interior extending throughout, or for a substantial part of, the length of the said component, which component is reinforced by suitable reinforcing members embedded in the concrete adjacently to the said hollow interior.

Preferably the said reinforcing members comprise rods or wires of steel or other suitable material extending parallel with the said hollow interior, together with wires of like material bent to a shape conforming to the cross-sectional shape of thev hollow interior, the several reinforcing members being preferably joined one to another to form a framework.

In a preferred form. of the invention, a component substantially as described is so formed as to have two or more hollow interiors of the kind described suitably spaced one from another and extending parallel to each other throughout, or for a substantial part of, the length of the said component. 1 a

The chief advantage accruing from the inven tion is found in its reducing the cost of components manufactured in accordance therewith. By making it practicable to cast components in concrete of a firmer original consistency, the invention effects a considerable saving of the time required for the setting of castings, and also effects a reduction of the amount of casting I equipment required for a plant of givencapacity,

this reduction being due to the fact that parts of the casting equipment are more quickly released for re-use.

Moreover, the speeding-up of production reduces overhead and other costs attendant upon the casting process. Material, too, can be saved, because by the use of reinforcing frameworks as described, cores need not be left -in the castings until setting or hardening has understood and readily, carried into effect, em-

bodiments thereof will now be fully described by way of example, with reference to the accompanying drawing, in which:

Figure 1 represents a perspective cross-sectional end View of part of a simple component according to the invention;

mold;

The speedy releasing of molding,

of the simpler beam illustrated in Figure 1.

Figure 3 represents a side elevation of a mold which corresponds to that shown in Figure 2;

Figure represents a side elevationof a core;

Figure 5 represents an end elevation of the core shown in Figure 4 and Figure 6 represents a crosssectionalend elvation of part of a floor constructed of components.

A simple component made in accordance with,

the invention may be as represented in Figure 1,

Y which shows the end portion of a component formed as a beam. A mass of concrete I has been cast around a core'whose withdrawal left a hollow interior 2 which may extend throughout the length of the beam but need not, be continuous. Around the hollow interior 2 are rein- 5, each of which preferably extends throughout the length of the beam and parallel with the hol-' ing members thus form a framework around the hollow interior 2, and assist in maintaining the forcing members comprising steel rods 3; 4 and shape thereof after early withdrawal of the core.

The resultant beam is particularly well adapted to be used as a component in the construc- F tion of afioor or the like, for which purpose a series of such beams can be laid in juxtaposition side by side,.in the mannershown in respect oi more complex beams'in Figure 6. I F

one of the more complex beams just mentioned,'also means and a method for its manuwith reference to Figures? and 3. It will be un derstood that this description suffices to disclose also means and a method for the manufacture The more complex beam .is very similar to that of two hollow interiors 2 instead of one as in the simpler beam. The mass of concrete 8 has been a cast around four tapered cores 9 (two having been inserted from each end of the mold), which 'cores, preferably of suitable'metal, are shownin position. The cores 9 may be of normal form but are preferably made with a pronounced tafacture, will now be described byway of example Figure 1, the main difierence being that there are per, as shown. 'It willbe observed that an effect ofthis taper is not onlyto facilitate withdrawal of the core,'but also assures that the proportion 'of concrete in relation to cavity in a cross-section of the component at a point near the inner,

smaller, end of the core is greater than in a crosssection near the outer, larger,' end. Thus-the com'ponent,,if a beam, is stronger at that part of its length where it is most subject to stress. In the case of the beam represented in Figure 2,

freiriforcing members comprise two lower longitudinal rods I0 and two upper longitudinal rods I I welded or otherwise attached to a series of transverse stirrups I2, of which one is shown; these stirrups being somewhat different in form from the stirrup shown in Figure 1. Other suitable 7 alternative forms may be used for the reinforcing rods and stirrups.

In Figure 2the beam is shown still in the mold wherein-it has been cast. In this example the mold, which may vary considerably in details of construction, comprises a pallet I3 of channel form composed of wooden boards, this pallet having a metal lining I4. The upper parts I5 which complete the sides of the mold are held therein.

.crete plugs shaped for the" purpose.

2,357,968 V in position by dowels I6, andthe mold generallyis held together by metal clamps I'I, I8 provided with transverse bolts I9 with wing-nuts 20. The clamps I! may conveniently have their top parts 2| arched as shown, to provide means for the liftingof the mold. Wedges 22 are adaptedto fit between the upper parts I5 of the sides of the mold and the'horizontal parts of the clamps II, I8, to exert vertical'pressure for the closing of the mold. Theends of the mold are closed by blocking pieces 23. shaped to fit transversely into the mold and adapted to be suitably secured Each of the blocking pieces 23 is pierced with two. holes, each of which holes is suitably located and formed to' receive one of'the tapered cores 9 and to hold it in position for casting. In order to ensure that the inner ends of the cores 9 shall not tip upwardly in the mold, each of the clamps I8 has a bolt 24 passing through its upper part as shown and so placed that when, the cores 9 are properly inserted each makes contact upwardly with one of these bolts 24. The bolts 24 also serve the purpose of providing rests whereon the reinforcing members II I can be placed to hold them in correct position for the casting operation. It will be noted that the stirrups fit around the cores so that the reinforcing members cannot rise during vibration of the mold. In order to facilitate. the'inserting and withdrawing of the cores 9, each has its'larger end 25 thickened asshown and fitted with tommy-bar holes 26, or With other suitable means of control. Vent-holes I in the ends of the core admit air to the cavity as the cores are withdrawn. Alternatively the coresmay have open links and be held in alignment by suitable means. In the casting operation, the mold is first'adjusted with all its partsassembled in correct position, the blocking pieces 23 being in their places. The reinforcing members III, II, I2 are inserted with the rods II resting on thebolts 24, and the stirrups I2 depending. Then the cores 9 are inserted until, having passed through the stirrups I2, they fit tightly in the holes in the blocking pieces 23 and bear upwardly against the bolts 24. Finally, concrete of. a firm'consistency is fed into the mold. The concrete should be just oil the slump, that is, in a sufficiently cohesive condition to be self-supporting, without having set;: it should be in a stifi .plasticcondi tion, stiff enough not to collapse when the'cores are withdrawn after consolidation, but not so dry as to contain insufiicient water to hydrate the cement. With the concrete in this condition proper penetration of the concrete into the interstices of the mold is practicable only if such penetration is assisted .by'applying some method of consolidation, e. g. vibration. Therefore at the same time as the concrete is being fed into the mold, either the mold (with the concrete) or I ging serves to strengthen the ends of the beams,

imposed masonry or other superstructure.-

When. parts of one mold have been removed,

they may be assembled on another pallet, and the various depths, if upper parts of the mold in various sizes are available.

The fact that the metal cores 9 are removed immediately after the casting of concrete components manufactured in accordance with the invention, results in a saving of metal, as well as in other economies.

Components in accordance with the invention may be assembled to form a floor in the manner illustrated in Figure 6. Components are juxtaposed side by side as shown, and the spaces left between their sloping upper sides are filled-in with grouting of concrete, so that a continuou upper surface of concrete is produced.

Although a component of the form shown in Figure 2, provided with two hollow interiors 2, is preferred for general use, the simpler component shown in Figure 1 is particularly suitable in the construction of deep beams intended to support heavy loads, which beams are necessarily themselves heavy; naturally they are lighter and more convenient to handle, if made in the simpler form.

It will be understood that although components with only one hollow'interior and components with two hollow interiors have been described, by slight modifications of the means disclosed the invention could be adapted for the production of components having three or more hollow interiors. Moreover, considerable variations of the form of the reinforcing framework around a given pallet can be used for making beams of the hollow interiors can be made in accordance with the invention.

It will also be understood that the outside shapes of components made in accordance with the invention are by no means limited to the shapes illustrated, these being shown merely as adapted to facilitate the assembling of components for the construction of continuous floors.

What I claim and desire to secure by Letters Patent of the United States is:-

1. The method of molding reinforced hollow concrete beams and the like, which comprises re-.

movably placing an elongated corein an elongated horizontal mold, applying around said core concrete while in plastic condition, subjecting said concrete to a consolidating treatment, said concrete being reinforced against collapse at spaced intervals closely adjacent the core, and

ciable contraction of the cavity has occurred in the process of setting or hardening of the con- ,be molded is crete.

2. In the method according to claim 1, said core being affixed at one end only, the stepwhich comprises holding the other end of said core against upward displacement when said concrete is applied and consolidated.

3. In combination, a horizontal mold having removable sides and an elongated hollow core removably placed horizontally in said mold and affixed at one end only to the mold, and stop means removably affixed to said sides and extending at least partially across the, interior of the mold center, whereby to limit the rising of the other end of said core when the material to placed in said mold.

ALAN MATHER PENNINGTON. 

